Systems, devices and methods related to paint recirculation during manufacture of radio-frequency modules

ABSTRACT

In applications such as manufacture of shielded radio-frequency modules where costly metallic paint is sprayed to form a conductive layer, it is desirable to reduce the amount of paint being utilized, and to maintain an acceptable level of suspension of paint particles in solution. A closed recirculation system can be configured to provide such desirable features, and can include a reservoir for holding a volume of metallic paint, a spray apparatus for spraying metallic paint received from the reservoir, and a recirculator for recirculating the metallic paint that is not sprayed back to the reservoir. In some embodiments, the recirculator can include a compact peristaltic pump that allows use of shorter fluid paths in the closed recirculation system, as well as a desired level of agitation to quickly achieve the acceptable level of suspension and maintain the suspension for an extended period of time.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Nos.61/700,394 filed Sep. 13, 2012 and entitled “SYSTEMS AND METHODS RELATEDTO PAINT RECIRCULATION,” and 61/700,398 filed Sep. 13, 2012 and entitled“SYSTEMS AND METHODS RELATED TO SPRAY-PAINTING FLUID PATH,” each ofwhich is expressly incorporated by reference herein in its entirety.

BACKGROUND

1. Field

The present disclosure generally relates to systems, devices and methodsrelated to paint delivery and recirculation during manufacture ofradio-frequency modules.

2. Description of the Related Art

In some applications involving packaging of radio-frequency (RF)modules, an array of such modules can be fabricated in an array on apanel. An overmold structure can be formed on the panel to encapsulatevarious components of the modules. A conductive layer such as metallicpaint can be formed on a surface of such an overmold structure. Such aconductive layer, in conjunction with RF shielding structures such asshielding wirebonds and a ground plane, can provide effective shieldingfunctionality for the modules.

SUMMARY

According to a number of implementations, the present disclosure relatesto a painting system for fabricating electronic modules. The systemincludes a reservoir having an input and an output, with the reservoirbeing implemented to hold a volume of metallic paint. The system furtherincludes a recirculator coupled to the reservoir and implemented toreceive metallic paint that has left the output of the reservoir andpump the metallic paint back to the input of the reservoir byperistalsis action to agitate the volume of metallic paint in thereservoir.

In some embodiments, the system can further include a spray apparatusimplemented between the output of the reservoir and the recirculator.The spray apparatus can include a nozzle assembly configured to becapable of spraying the metallic paint. The spray apparatus can includea selector configured to route the metallic paint to either the nozzleassembly for spraying of the metallic paint or the recirculator forpumping the metallic paint back to the reservoir. The selector caninclude a seal mechanism.

In some embodiments, the recirculator can include a peristaltic pump.The peristaltic pump can be a rotary-type peristaltic pump. Theperistaltic pump can be configured to operate at different speeds toyield different flow rates.

In some embodiments, a recirculating path defined by a path from thereservoir to the spray apparatus, a path from the spray apparatus to theperistaltic pump, and a path from the peristaltic pump to the reservoir,can be substantially closed to inhibit vaporization loss. Therecirculating path can have a length that is less than approximately 30inches to reduce a purging volume. The length can be less thanapproximately 15 inches.

In some embodiments, a relatively compact size of the peristaltic pumpcan allow the spray apparatus and the reservoir to be positionedrelatively close to the peristaltic pump, thereby allowing a relativelyshort length for the recirculating path. In some embodiments, each ofthe path from the spray apparatus to the peristaltic pump and the pathfrom the peristaltic pump to the reservoir can include a tubing having abore diameter selected to yield a desired flow rate of the recirculatingpath. An increase in the bore diameter can result in an increase in theflow rate.

In some embodiments, the reservoir can further include a gas inputconfigured to receive a pressurized gas to push the metallic paint fromthe reservoir to the spray apparatus.

In some embodiments, the system can be capable of establishing a desiredlevel of suspension for the metallic paint from a separated state withinapproximately 5 minutes. The system can be capable of substantiallymaintaining the desired level of suspension for at least 9 hours, and insome situations, for at least 12 hours.

In a number of implementations, the present disclosure relates to arecirculating system for agitating metallic paint awaitingspray-application to form a conductive layer for one or more electronicmodules. The system includes a peristaltic pump configured to pump themetallic paint from a reservoir and return unsprayed metallic paint tothe reservoir.

In accordance with some teachings, the present disclosure relates to amethod for agitating metallic paint. The method includes providingmetallic paint in a reservoir. The method further includes pumping themetallic paint from the reservoir by peristalsis action. The methodfurther includes returning the pumped metallic paint back to thereservoir so that the returned metallic paint has a desired level ofsuspension of metal particles in a solvent of the metallic paint.

In some implementations, the present disclosure relates to a method forapplying metallic paint during fabrication of electronic modules. Themethod includes providing a reservoir to hold a volume of metallic paintawaiting spray-application, with the reservoir including an input and anoutput. The method further includes providing a spray apparatus capableof being in a spray mode and a recirculate mode. The method furtherincludes providing the metallic paint from the reservoir to the sprayapparatus through a first path to allow spray-application of themetallic paint when the spray apparatus is in the spray mode. The methodfurther includes returning the metallic paint from the spray apparatusto the reservoir through a second path by peristalsis when the sprayapparatus is in the recirculate mode.

According to some implementations, the present disclosure relates to apainting system for fabricating electronic modules. The system includesa reservoir implemented to hold a volume of metallic paint. The systemfurther includes a spray apparatus coupled to the reservoir. The sprayapparatus includes a chamber that defines an input port implemented toreceive metallic paint from the reservoir, an output port implemented toallow spray-application of the metallic paint when in a spray mode, anda return port implemented to allow return of the metallic paint back tothe reservoir when not in the spray mode. The input port and the returnport are positioned at a substantially common height in the chamber toaccommodate a reduced vertical dimension of the chamber and to promote adesired flow of the metallic paint between the input port and the returnport.

In some embodiments, the system can further include a recirculatorcoupled to the return port of the chamber and implemented to recirculatethe metallic paint back to the reservoir. The recirculator can include aperistaltic pump.

In some embodiments, the spray apparatus can further include a selectorimplemented to allow the spray apparatus to switch between the spray andrecirculate modes. The selector can include a sealing mechanism. Thechamber can have a cylindrical shape such that the output port ispositioned on a floor of the cylinder and each of the input and port andthe return port is defined on a wall of the cylinder. The substantiallycommon height of the input port and the return port can allow thecylinder to have a reduced or minimum height. The sealing mechanism suchas a U-cup seal can be positioned at a ceiling of the cylinder. Thereduced or minimum height of the cylinder can allow the sealingmechanism to be positioned closer to the output port to thereby reducethe amount of features where flakes from the metallic paint are likelyto accumulate.

In some embodiments, the spray apparatus can further include a nozzleassembly implemented to receive the metallic paint through the outputport and generate an output spray. The nozzle assembly can include a gasport for receiving pressurized gas to facilitate atomization of theoutput spray.

In accordance with a number of implementations, the present disclosurerelates to a chamber for a spray apparatus. The chamber includes aninput port implemented to allow receiving of paint having a relativelyquick settling property. The chamber further includes an output portimplemented to allow spray-application of the paint from the chamber.The chamber further includes a return port implemented to allow removalof the paint that is not sprayed. The return port is positioned relativeto the input port to reduce the volume of the chamber and to reduce thelikelihood of accumulation of paint particles within the chamber.

In some embodiments, the paint particles can include metallic flakes. Insome embodiments, the chamber can define a cylindrical volume, with theoutput port being positioned at a floor of the cylindrical volume, andthe input and return ports being positioned at a side wall of thecylindrical volume. The input and return ports can be positioned atapproximately the same height from the floor to thereby allow reductionof minimization of a length of the cylindrical volume. The input andreturn ports can be positioned so that an azimuthal angle between theinput port and the return port is in a range of approximately 60 to 120degrees. For example, the azimuthal angle between the input port and thereturn port can be approximately 90 degrees.

According to some implementations, the present disclosure relates to aspray apparatus that includes a chamber configured to receive paint. Thechamber includes a first cap, a second cap, and a side wall between thefirst cap and the second cap. The spray apparatus further includes aninput port defined by the side wall of the chamber, with the input portbeing configured to provide an input path for the paint. The sprayapparatus further includes a return port defined by the side wall of thechamber, with the return port being configured to provide arecirculation exit path for the paint. The input port and the returnport can be positioned at approximately the same distance from the firstcap. The spray apparatus further includes an output port defined by thefirst cap. The output port is configured to provide a spray exit pathfor the paint, and includes a valve seating surface. The spray apparatusfurther includes a valve pin having a tip dimensioned to mate with thevalve seating surface of the output port to substantially seal theoutput port when the spray apparatus is in a recirculation mode. Thevalve pin is configured to retract away from the valve seating surfaceto open the output port when the spray apparatus is in a spray mode.

In some embodiments, the valve pin can extend through the second cap.The valve pin can include an air piston configured to receivepressurized air to allow the valve pin to be retracted. The sprayapparatus can further include a return spring assembly coupled to thevalve pin. The return spring assembly can be configured to allow thevalve pin to return to the seated position when the application ofpressurized air ceases. The second cap can include a seal configured toallow the retracting and return motions of the valve pin whileinhibiting passage of paint from the chamber through the second cap. Thespray apparatus can further include an adjustment device coupled to thevalve pin. The adjustment device can be configured to adjust a traveldistance of the retracting motion of the valve pin.

For purposes of summarizing the disclosure, certain aspects, advantagesand novel features of the inventions have been described herein. It isto be understood that not necessarily all such advantages may beachieved in accordance with any particular embodiment of the invention.Thus, the invention may be embodied or carried out in a manner thatachieves or optimizes one advantage or group of advantages as taughtherein without necessarily achieving other advantages as may be taughtor suggested herein.

The present disclosure relates to U.S. patent application Ser. No.______ [Attorney Docket 75900-50017], titled “SYSTEMS, DEVICES ANDMETHODS RELATED TO SPRAY-PAINTING FLUID PATH FOR MANUFACTURE OFRADIO-FREQUENCY MODULES,” filed on even date herewith and herebyincorporated by reference herein in its entirety.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a process that can be implemented to fabricate a packagedmodule that includes a die having an integrated circuit (IC).

FIGS. 2A1 and 2A2 show front and back sides of an example laminate panelconfigured to receive a plurality of dies for formation of packagedmodules.

FIGS. 2B1 to 2B3 show various views of a laminate substrate of the panelconfigured to yield an individual module.

FIG. 2C shows an example of a fabricated semiconductor wafer having aplurality of dies that can be singulated for mounting on the laminatesubstrate.

FIG. 2D depicts an individual die showing example electrical contactpads for facilitating connectivity when mounted on the laminatesubstrate.

FIGS. 2E1 and 2E2 show various views of the laminate substrate beingprepared for mounting of example surface-mount technology (SMT) devices.

FIGS. 2F1 and 2F2 show various views of the example SMT devices mountedon the laminate substrate.

FIGS. 2G1 and 2G2 show various views of the laminate substrate beingprepared for mounting of an example die.

FIGS. 2H1 and 2H2 show various views of the example die mounted on thelaminate substrate.

FIGS. 21I and 212 show various views of the die electrically connectedto the laminate substrate by example wirebonds.

FIGS. 2J1 and 2J2 show various views of wirebonds formed on the laminatesubstrate and configured to facilitate electromagnetic (EM) isolationbetween an area defined by the wirebonds and areas outside of thewirebonds.

FIG. 2K shows a side view of molding configuration for introducingmolding compound to a region above the laminate substrate.

FIG. 2L shows a side view of an overmold formed via the moldingconfiguration of FIG. 2K.

FIG. 2M shows the front side of a panel with the overmold.

FIG. 2N shows a side view of how an upper portion of the overmold can beremoved to expose upper portions of the EM isolation wirebonds.

FIG. 2O shows a portion of a panel where a portion of the overmold hasits upper portion removed to better expose the upper portions of the EMisolation wirebonds.

FIG. 2P shows a side view of a conductive layer formed over the overmoldsuch that the conductive layer is in electrical contact with the exposedupper portions of the EM isolation wirebonds.

FIG. 2Q shows a panel where the conductive layer can be a spray-onmetallic paint.

FIG. 2R shows individual packaged modules being cut from the panel.

FIGS. 2S1 to 2S3 show various views of an individual packaged module.

FIG. 2T shows that one or more of modules that are mounted on a circuitboard such as a wireless phone board can include one or more features asdescribed herein.

FIG. 3A shows a process that can be implemented to install a packagedmodule having one or more features as described herein on the circuitboard of FIG. 2T.

FIG. 3B schematically depicts the circuit board with the packaged moduleinstalled thereon.

FIG. 3C schematically depicts a wireless device having the circuit boardwith the packaged module installed thereon.

FIG. 4 schematically depicts a painting system that can be utilized toapply metallic paint such as a conductive layer of FIGS. 2P and 2Q,where the painting system can include a paint reservoir, a sprayapparatus, and a recirculating apparatus.

FIG. 5 depicts an example configuration of the painting system where therecirculating apparatus can include a peristaltic pump.

FIG. 6 shows an example of a working painting system of FIG. 5.

FIGS. 7A-7D show examples of how the recirculating apparatus can readilyagitate metallic paint to form and maintain a desired suspension ofparticles in solution.

FIGS. 8A-8C show an example of how the recirculating apparatus canmaintain a desired suspension of particles over time during operation.

FIGS. 9A and 9B show examples of the suspension properties and resultingpainted-layer quality during the operating period of FIGS. 8A-8C.

FIG. 10 shows an example of the spray apparatus of FIG. 4.

FIG. 11 shows another example of the spray apparatus of FIG. 4.

FIG. 12 schematically depicts the spray apparatus of FIG. 10.

FIGS. 13A and 13B schematically depict the spray apparatus of FIG. 11.

FIGS. 14A and 14B schematically depict how the spray apparatus of FIGS.11 and 13 can operate in a recirculate mode and a spray mode.

FIG. 15 schematically depicts an example of how an input and arecirculating-output of the spray apparatus of FIGS. 11, 13 and 14 canbe configured.

FIGS. 16A and 16B show non-limiting examples of how theinput/recirculating-output arrangement can be modified.

FIGS. 17A-17E show various examples of a paint chamber of a spray head,and how such a spray head can be configured to switch between a spraymode and a recirculate mode.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

The headings provided herein, if any, are for convenience only and donot necessarily affect the scope or meaning of the claimed invention.

Described herein are various examples of systems, apparatus, devicesstructures, materials and/or methods related to fabrication of packagedmodules having a radio-frequency (RF) circuit and wirebond-basedelectromagnetic (EM) isolation structures. Although described in thecontext of RF circuits, one or more features described herein can alsobe utilized in packaging applications involving non-RF components.Similarly, one or more features described herein can also be utilized inpackaging applications without the EM isolation functionality.

FIG. 1 shows a process 10 that can be implemented to fabricate apackaged module having and/or via one or more features as describedherein.

FIG. 2 shows various parts and/or stages of various steps associatedwith the process 10 of FIG. 1.

In block 12 a of FIG. 1, a packaging substrate and parts to be mountedon the packaging substrate can be provided. Such parts can include, forexample, one or more surface-mount technology (SMT) components and oneor more singulated dies having integrated circuits (ICs). FIGS. 2A1 and2A2 show that in some embodiments, the packaging substrate can include alaminate panel 16. FIG. 2A1 shows the example panel's front side; andFIG. 2A2 shows the panel's back side. The panel 16 can include aplurality of individual module substrates 20 arranged in groups that aresometimes referred to as cookies 18.

FIGS. 2B1-2B3 show front, side and back, respectively, of an exampleconfiguration of the individual module substrate 20. For the purpose ofdescription herein, a boundary 22 can define an area occupied by themodule substrate 20 on the panel 16. Within the boundary 22, the modulesubstrate 20 can include a front surface 21 and a back surface 27. Shownon the front surface 21 is an example mounting area 23 dimensioned toreceive a die (not shown). A plurality of example contact pads 24 (e.g.,connection wirebond contact pads) are arranged about the die-receivingarea 23 so as to allow formation of electrical connections between thedie and contact pads 28 arranged on the back surface 27. Although notshown, electrical connections between the wirebond contact pads 24 andthe module's contact pads 28 can be configured in a number of ways. Alsowithin the boundary 22 are two sets of example contact pads 25configured to allow mounting of, for example passive SMT devices (notshown). The contact pads 25 can be electrically connected to some of themodule's contact pads 28 and/or ground contact pads 29 disposed on theback surface 27. Also within the boundary 22 are a plurality of wirebondpads 26 configured to allow formation of a plurality of EM-isolatingwirebonds (not shown). The wirebond pads 26 can be electricallyconnected to an electrical reference plane (such as a ground plane) 30.Such connections between the wirebond pads 26 and the ground plane 30(depicted as dotted lines 31) can be achieved in a number of ways. Insome embodiments, the ground plane 30 may or may not be connected to theground contact pads 29 disposed on the back surface 27.

FIG. 2C shows an example fabricated wafer 35 that includes a pluralityof functional dies 36 awaiting to be cut (or sometimes referred to assingulated) into individual dies. Such cutting of the dies 36 can beachieved in a number of ways. FIG. 2D schematically depicts anindividual die 36 where a plurality of metalized contact pads 37 can beprovided. Such contact pads can be configured to allow formation ofconnection wirebonds between the die 36 and the contact pads 24 of themodule substrate (e.g., FIG. 2B1).

In block 12 b of FIG. 1, solder paste can be applied on the modulesubstrate to allow mounting of one or more SMT devices. FIGS. 2E1 and2E2 show an example configuration 40 where solder paste 41 is providedon each of the contact pads 25 on the front surface of the modulesubstrate 20. In some implementations, the solder paste 41 can beapplied to desired locations on the panel (e.g., 16 in FIG. 2A1) indesired amount by an SMT stencil printer.

In block 12 c of FIG. 1, one or more SMT devices can be positioned onthe solder contacts having solder paste. FIGS. 2F1 and 2F2 show anexample configuration 42 where example SMT devices 43 are positioned onthe solder paste 41 provided on each of the contact pads 25. In someimplementations, the SMT devices 43 can be positioned on desiredlocations on the panel by an automated machine that is fed with SMTdevices from tape reels.

In block 12 d of FIG. 1, a reflow operation can be performed to melt thesolder paste to solder the one or more SMT devices on their respectivecontact pads. In some implementations, the solder paste 41 can beselected and the reflow operation can be performed to melt the solderpaste 41 at a first temperature to thereby allow formation of desiredsolder contacts between the contact pads 25 and the SMT devices 43.

In block 12 e of FIG. 1, solder residue from the reflow operation ofblock 12 d can be removed. By way of an example, the substrates can berun through a solvent or aqueous cleaning step. Such a cleaning step canbe achieved by, for example, a nozzle spray, vapor chamber, or fullimmersion in liquid.

In block 12 f of FIG. 1, adhesive can be applied on one or more selectedareas on the module substrate 20 to allow mounting of one or more dies.

FIGS. 2G1 and 2G2 show an example configuration 44 where adhesive 45 isapplied in the die-mounting area 23. In some implementations, theadhesive 45 can be applied to desired locations on the panel (e.g., 16in FIG. 2A1) in desired amount by techniques such as screen printing.

In block 12 g of FIG. 1, one or more dies can be positioned on theselected areas with adhesive applied thereon. FIGS. 2H1 and 2H2 show anexample configuration 46 where an example die 36 is positioned on thedie-mounting area 23 via the adhesive 45. In some implementations, thedie 36 can be positioned on the die-mounting area on the panel by anautomated machine that is fed with dies from a tape reel.

In block 12 h of FIG. 1, the adhesive between the die the die-mountingarea can be cured. Preferably, such a curing operation can be performedat one or more temperatures that are lower than the above-describedreflow operation for mounting of the one or more SMT devices on theirrespective contact pads. Such a configuration allows the solderconnections of the SMT devices to remain intact during the curingoperation.

In block 12 j of FIG. 1, electrical connections such as wirebonds can beformed between the mounted die(s) and corresponding contact pads on themodule substrate 20. FIGS. 21I and 212 show an example configuration 48where a number of wirebonds 49 are formed between the contact pads 37 ofthe die 36 and the contact pads 24 of the module substrate 20. Suchwirebonds can provide electrical connections for signals and/or power toand from one or more circuits of the die 36. In some implementations,the formation of the foregoing wirebonds can be achieved by an automatedwirebonding machine.

In block 12 k of FIG. 1, a plurality of RF-shielding wirebonds can beformed about a selected area on the module substrate 20. FIGS. 2J1 and2J2 show an example configuration 50 where a plurality of RF-shieldingwirebonds 51 are formed on wirebond pads 26. The wirebond pads 26 areschematically depicted as being electrically connected (dotted lines 31)with one or more reference planes such as a ground plane 30. In someembodiments, such a ground plane can be disposed within the modulesubstrate 20. The foregoing electrical connections between theRF-shielding wirebonds 51 and the ground plane 30 can yield aninterconnected RF-shielding structure at sides and underside of the areadefined by the RF-shielding wirebonds 51. As described herein, aconductive layer can be formed above such an area and connected to upperportions of the RF-shielding wirebonds 51 to thereby form an RF-shieldedvolume.

In the example configuration 50, the RF-shielding wirebonds 51 are shownto form a perimeter around the area where the die (36) and the SMTdevices (43) are located. Other perimeter configurations are alsopossible. For example, a perimeter can be formed with RF-wirebondsaround the die, around one or more of the SMT devices, or anycombination thereof. In some implementations, an RF-wirebond-basedperimeter can be formed around any circuit, device, component or areawhere RF-isolation is desired. For the purpose of description, it willbe understood that RF-isolation can include keeping RF signals or noisefrom entering or leaving a given shielded area.

In the example configuration 50, the RF-shielding wirebonds 51 are shownto have an asymmetrical side profile configured to facilitate controlleddeformation during a molding process as described herein. Additionaldetails concerning such wirebonds can be found in, for example, PCTPublication No. WO 2010/014103 titled “SEMICONDUCTOR PACKAGE WITHINTEGRATED INTERFERENCE SHIELDING AND METHOD OF MANUFACTURE THEREOF.” Insome embodiments, other shaped RF-shielding wirebonds can also beutilized. For example, generally symmetric arch-shaped wirebonds asdescribed in U.S. Pat. No. 8,071,431, titled “OVERMOLDED SEMICONDUCTORPACKAGE WITH A WIREBOND CAGE FOR EMI SHIELDING,” can be used asRF-shielding wirebonds in place of or in combination with the shownasymmetric wirebonds. In some embodiments, RF-shielding wirebonds do notnecessarily need to form a loop shape and have both ends on the surfaceof the module substrate. For example, wire extensions with one end onthe surface of the module substrate and the other end positioned abovethe surface (for connecting to an upper conductive layer) can also beutilized.

In the example configuration 50 of FIGS. 2J1 and 2J2, the RF-shieldingwirebonds 51 are shown to have similar heights that are generally higherthan heights of the die-connecting wirebonds (49). Such a configurationallows the die-connecting wirebonds (49) to be encapsulated by moldingcompound as described herein, and be isolated from an upper conductivelayer to be formed after the molding process.

In block 12 l of FIG. 1, an overmold can be formed over the SMTcomponent(s), die(s), and RF-shielding wirebonds. FIG. 2K shows anexample configuration 52 that can facilitate formation of such anovermold. A mold cap 53 is shown to be positioned above the modulesubstrate 20 so that the lower surface 54 of the mold cap 53 and theupper surface 21 of the module substrate 20 define a volume 55 wheremolding compound can be introduced.

In some implementations, the mold cap 53 can be positioned so that itslower surface 54 engages and pushes down on the upper portions of theRF-shielding wirebonds 51. Such a configuration allows whatever heightvariations in the RF-shielding wirebonds 51 to be removed so that theupper portions touching the lower surface 54 of the mold cap 53 are atsubstantially the same height. When the mold compound is introduced andan overmold structure is formed, the foregoing technique maintains theupper portions of the encapsulated RF-shielding wirebonds 51 at or closeto the resulting upper surface of the overmold structure.

In the example molding configuration 52 of FIG. 2K, molding compound canbe introduced from one or more sides of the molding volume 55 asindicated by arrows 56. In some implementations, such an introduction ofmolding compound can be performed under heated and vacuum condition tofacilitate easier flow of the heated molding compound into the volume55.

FIG. 2L shows an example configuration 58 where molding compound hasbeen introduced into the volume 55 as described in reference to FIG. 2Kand the molding cap removed to yield an overmold structure 59 thatencapsulates the various parts (e.g., die, die-connecting wirebonds, andSMT devices). The RF-shielding wirebonds are also shown to besubstantially encapsulated by the overmold structure 59. The upperportions of the RF-shielding wirebonds are shown to be at or close tothe upper surface 60 of the overmold structure 59.

FIG. 2M shows an example panel 62 that has overmold structures 59 formedover the multiple cookie sections. Each cookie section's overmoldstructure can be formed as described herein in reference to FIGS. 2K and2L. The resulting overmold structure 59 is shown to define a commonupper surface 60 that covers the multiple modules of a given cookiesection.

The molding process described herein in reference to FIGS. 2K-2M canyield a configuration where upper portions of the encapsulatedRF-shielding wirebonds are at or close to the upper surface of theovermold structure. Such a configuration may or may not result in theRF-shielding wirebonds forming a reliable electrical connection with anupper conductor layer to be formed thereon.

In block 12 m of FIG. 1, a top portion of the overmold structure can beremoved to better expose upper portions of the RF-shielding wirebonds.FIG. 2N shows an example configuration 64 where such a removal has beenperformed. In the example, the upper portion of the overmold structure59 is shown to be removed to yield a new upper surface 65 that is lowerthan the original upper surface 60 (from the molding process). Such aremoval of material is shown to better expose the upper portions 66 ofthe RF-shielding wirebonds 51.

The foregoing removal of material from the upper portion of the overmoldstructure 59 can be achieved in a number of ways. FIG. 2O shows anexample configuration 68 where such removal of material is achieved bysand-blasting. In the example, the left portion is where material hasbeen removed to yield the new upper surface 65 and better exposed upperportions 66 of the RF-shielding wirebonds. The right portion is wherematerial has not been removed, so that the original upper surface 60still remains. The region indicated as 69 is where the material-removalis being performed.

In the example shown in FIG. 2O, a modular structure corresponding tothe underlying module substrate 20 (depicted with a dotted box 22) isreadily apparent from the exposed upper portions 66 of the RF-shieldingwirebonds that are mostly encapsulated by the overmold structure 59.Such modules will be separated after a conductive layer is formed overthe newly formed upper surface 65.

In block 12 n of FIG. 1, the new exposed upper surface resulting fromthe removal of material can be cleaned. By way of an example, thesubstrates can be run through a solvent or aqueous cleaning step. Such acleaning step can be achieved by, for example, a nozzle spray, or fullimmersion in liquid.

In block 12 o of FIG. 1, an electrically conductive layer can be formedon the new exposed upper surface of the overmold structure, so that theconductive layer is in electrical contact with the upper portions of theRF-shielding wirebonds. Such a conductive layer can be formed by anumber of different techniques, including methods such as spraying orprinting.

FIG. 2P shows an example configuration 70 where an electricallyconductive layer 71 has been formed over the upper surface 65 of theovermold structure 59. As described herein, the upper surface 65 betterexposes the upper portions 66 of the RF-shielding wirebonds 51.Accordingly, the formed conductive layer 71 forms improved contacts withthe upper portions 66 of the RF-shielding wirebonds 51.

As described in reference to FIG. 2J, the RF-shielding wirebonds 51 andthe ground plane 30 can yield an interconnected RF-shielding structureat sides and underside of the area defined by the RF-shielding wirebonds51. With the upper conductive layer 71 in electrical contact with theRF-shielding wirebonds 51, the upper side above the area is now shieldedas well, thereby yielding a shielded volume.

FIG. 2Q shows an example panel 72 that has been sprayed with conductivepaint to yield an electrically conductive layer 71 that covers multiplecookie sections. As described in reference to FIG. 2M, each cookiesection includes multiple modules that will be separated.

In block 12 p of FIG. 1, the modules in a cookie section having a commonconductive layer (e.g., a conductive paint layer) can be singulated intoindividual packaged modules. Such singulation of modules can be achievedin a number of ways, including a sawing technique.

FIG. 2R shows an example configuration 74 where the modular section 20described herein has been singulated into a separated module 75. Theovermold portion is shown to include a side wall 77; and the modulesubstrate portion is shown to include a side wall 76. Collectively, theside walls 77 and 76 are shown to define a side wall 78 of the separatedmodule 75. The upper portion of the separated module 75 remains coveredby the conductive layer 71. As described herein in reference to FIG. 2B,the lower surface 27 of the separated module 75 includes contact pads28, 29 to facilitate electrical connections between the module 75 and acircuit board such as a phone board.

FIGS. 2S1, 2S2 and 2S3 show front (also referred to as top herein), back(also referred to as bottom herein) and perspective views of thesingulated module 75. As described herein, such a module includesRF-shielding structures encapsulated within the overmold structure; andin some implementations, the overall dimensions of the module 75 is notnecessarily any larger than a module without the RF-shieldingfunctionality. Accordingly, modules having integrated RF-shieldingfunctionality can advantageously yield a more compact assembled circuitboard since external RF-shield structures are not needed. Further, thepackaged modular form allows the modules to be handled easier duringmanipulation and assembly processes.

In block 12 q of FIG. 1, the singulated modules can be tested for properfunctionality. As discussed above, the modular form allows such testingto be performed easier. Further, the module's internal RF-shieldingfunctionality allows such testing to be performed without externalRF-shielding devices.

FIG. 2T shows that in some embodiments, one or more of modules includedin a circuit board such as a wireless phone board can be configured withone or more packaging features as described herein. Non-limitingexamples of modules that can benefit from such packaging featuresinclude, but are not limited to, a controller module, an applicationprocessor module, an audio module, a display interface module, a memorymodule, a digital baseband processor module, GPS module, anaccelerometer module, a power management module, a transceiver module, aswitching module, and a power amplifier module.

FIG. 3A shows a process 80 that can be implemented to assemble apackaged module having one or more features as described herein on acircuit board. In block 82 a, a packaged module can be provided. In someembodiments, the packaged module can represent a module described inreference to FIG. 2T. In block 82 b, the packaged module can be mountedon a circuit board (e.g., a phone board). FIG. 3B schematically depictsa resulting circuit board 90 having module 91 mounted thereon. Thecircuit board can also include other features such as a plurality ofconnections 92 to facilitate operations of various modules mountedthereon.

In block 82 c, a circuit board having modules mounted thereon can beinstalled in a wireless device. FIG. 3C schematically depicts a wirelessdevice 94 (e.g., a cellular phone) having a circuit board 90 (e.g., aphone board). The circuit board 90 is shown to include a module 91having one or more features as described herein. The wireless device isshown to further include other components, such as an antenna 95, a userinterface 96, and a power supply 97.

As described in reference to FIGS. 2P and 2Q, the electricallyconductive layer 71 can be formed by, for example, spraying ofconductive paint. Such spraying of conductive paint can be performed ona given panel having multiple modular devices yet to be singulated.

Conductive paints used for such spraying applications typically havemetal flakes suspended in a solvent. A proper suspension is desirablesince it can affect the spray process, spray equipment, and/or qualityof the resulting conductive layer. For example, metal flakes canseparate from the solvent and settle on a lower portion of a paintreservoir, thereby yielding a gradient in metal flake density. Such agradient can affect spray-ability of some portions of such non-uniformpaint. If a more dense portion is sprayed, the paint can clog equipmentssuch as a spray head. The resulting sprayed-on conductive layer can haveuneven thickness as well as uneven metal distribution (thereby affectingreliability).

Described herein are examples of systems, devices, and methods foreffectively maintaining and delivering conductive paint such as metallicpaint. Although described in the context of spraying metallic paint toform a conductive layer on a panel having an array of modules, it willbe understood that one or more features of the present disclosure canalso be implemented in other application.

FIG. 4 schematically depicts a painting system 100 having a plurality ofcomponents that can allow metallic paint to be maintained with arelatively uniform suspension consistency, as well as deliver suchmetallic paint to a spray head for spray application. The system 100 caninclude a reservoir 102 configured to hold metallic paint and deliver(arrow 104) the paint to a spray apparatus 106. If the paint is to besprayed, the spray apparatus 106 can spray the paint (arrow 108) to apanel 110. If the spraying operation is not active, the paint deliveredto the spray apparatus 106 can be routed (arrow 112) to a recirculator114. The recirculator 114 can be configured to return the paint (arrow116) to the reservoir 102. As describe herein, the recirculator 114 canfacilitate achieving of and maintaining a desired level of suspension ofthe paint in an effective manner.

FIG. 4 shows that in some embodiments, at least some features associatedwith the painting system 100 can be facilitated by a controller 400.Such a controller can include or be in communication with a processor402 configured to facilitate such control functionalities. Suchfunctionalities can include, for example, switching between a spray mode(e.g., where paint is sprayed) and a recirculation mode (e.g., wherepaint is recirculated). Examples of such functionalities are describedherein in greater detail. In some embodiments, the controller 402 caninclude or be in communication with a computer readable medium (CRM),including a non-transitory CRM.

Various examples of the reservoir 102, the spray apparatus 106, and therecirculator 114 are described herein. FIGS. 5-9 are generally directedto various examples of the recirculator 114 and how it can beincorporated into a painting system to yield desirable results. FIGS.10-17 are generally directed to various examples of the spray apparatusand how it can be incorporated into a painting system to yield desirableresults. In some implementations, one or more features of therecirculator 114 can be combined with one or more features of the sprayapparatus 106. It will be understood, however, that each of therecirculator 114 and the spray apparatus 106 can operate withoutnecessarily relying on the features provided by the other component.

FIG. 5 shows that in some implementations, the recirculator 114 of FIG.4 can include a peristaltic pump 120 that receives, as input, paint(depicted as arrows 150) through a tube 130 a from a spray apparatus106. As described herein, the spray apparatus 106 can route the paint tothe peristaltic pump 120 when the paint is not being sprayed. It will beunderstood that functionalities and benefits associated with theperistaltic pump 120 to recirculate the paint can remain even if thespray apparatus 106 is absent or bypassed completely.

The example peristaltic pump 120 is shown to include a roller 124 withone or more wipers 126 that provide peristalsis action when rotated(arrow 128) against the tube (130 a and/or 130 b) backed by a shroud122. The peristalsis action of the pump 120 is shown to pump the inputpaint 150 as an output paint (arrows 152) that is returned to areservoir 102 through the output portion of the tube (130 b).

The foregoing peristalsis action of the pump 120 can provide agitationof the metallic paint, so that the paint within the circulation system(including the paint 132 in the reservoir 102) maintains a desired levelof suspension. As described herein, such a desired level of suspensioncan be achieved relatively quickly even from a separated state, andmaintained for a significant duration.

In FIG. 5, paint (arrow 146) from the reservoir 102 can be provided tothe spray apparatus 106 through a tube 144, thereby completing a circuitin the context of recirculation. Compressed gas (arrow 140) provided tothe reservoir 102 through a tube 142 can provide pressure to push thepaint from the reservoir 102 to the spray apparatus 106.

In some embodiments, the foregoing recirculation circuit can beimplemented as a closed system. The tube (130 a and/or 130 b) can remainclosed before (as portion 130 a), during, and/or after (as portion 130b) the peristalsis action. Thus, in addition to the agitating property,the peristaltic pump 120 can be particularly suitable for use in such aclosed system. In the context of metallic paints that typically havehigh vapor pressure solvents, the closed system facilitated by theperistaltic pump 120 can be particularly advantageous.

FIG. 6 shows an example of a working painting system of FIG. 5. In theexample shown, the reservoir 102 is dimensioned to hold approximately 55cc. The reservoir 102 is sometimes referred to herein as a storagecartridge. In some embodiments, such a storage cartridge can beconfigured to be refillable by an operator, be configured as adisposable module, or some combination thereof. Although described inthe context of the example 55 cc cartridge, cartridges having larger orsmaller volumes can also be utilized, and metallic paint stored andrecirculated therein can be maintained with a desired level ofsuspension by techniques described herein. For example, in a productionscale setting, a 6 oz cartridge can be used for smaller runs, and a 20oz cartridge can be used for a high-volume run. As described herein, theagitating feature of the peristaltic pump can be generally independentof the cartridge size. Thus, such flexibility in cartridge sizes can beprovided.

The example peristaltic pump 120 shown in FIG. 6 is a Watson-Marlow400F/B1 peristaltic pump. Such a pump can be operated at differentspeeds and/or with different tube bore sizes to achieve different flowrates. For example, such a pump operated at about 250 RPM can yield thefollowing example flow rates: 2.5 ml/min with a 0.5 mm tube bore size,7.5 ml/min with a 0.8 mm tube bore size, 27 ml/min with a 1.6 mm tubebore size, 60 ml/min with a 2.4 mm tube bore size, 103 ml/min with a 3.2mm tube bore size, and 148 ml/min with a 4.0 mm tube bore size.

One can see that the peristaltic pump 120 can be relatively small. Byusing such a small peristaltic pump it is possible to mount the pump 120close to or on an actual head of the spray system. Such an arrangementcan allow use of a relatively short fluid path (e.g., tubing portion 130a) between the spray apparatus 106 and the pump 120, as well as arelatively short fluid path (e.g., tubing portion 130 b) between thepump 120 and the reservoir 102. In some embodiments, the total length ofthe foregoing assembly of tubings can be less than or equal to about 30inches or 15 inches. For the example shown in FIG. 6, such a totallength is about 30 inches.

In some implementations, operating parameters such as the diameter oftubing line (130 a and/or 130 b) and rotational rate of the pump 120 canbe selected to, for example, yield desired turnover of the paint 132 tokeep the metal flakes in proper suspension, as well as to keep theamount of paint needed to purge the recirculation system to a minimum ora reduced amount. The foregoing examples of performance improvements canbe particularly useful for a number of reasons. For example, somemetallic paints include precious metal flakes and therefore arerelatively expensive. Thus, minimizing or reducing any waste of suchmetallic paints for the purging process can provide a significant costadvantage. In another example, the close proximity of the pump 120 fromthe spray apparatus 106 can allow the recirculation process to occurquicker and thereby maintain an acceptable level of suspensionuniformity over an extended period of time. Such features can be highlydesirable in high-volume manufacturing applications.

Although described in the context of a rotary-type peristaltic pump, itwill be understood that one or more features of the present disclosurecan be implemented in other types of peristaltic pump. For example, alinear-type peristaltic pump can be utilized.

In FIG. 6, a tube 142 is depicted as delivering compressed gas (e.g.,air) from a gas source to the upper portion of the reservoir 102 toprovide pressure to push the paint from the reservoir 102 to the sprayapparatus 106 (through tube 144). A tube 143 is depicted as deliveringcompressed gas (e.g., air) to the spray apparatus 106 to, for example,provide atomizer functionality. As shown, such compressed gas can beprovided from a source, through a tube 141 and an interface block.Additional details concerning such atomizer functionality are describedherein.

FIGS. 7-9 show examples of how one or more features described inreference to FIGS. 4-6 can allow metallic paint to reach a desiredsuspension state and maintain such a state for an extended period oftime during operation. In an example demonstration, and as shown in FIG.7A, a paint reservoir 102 was provided with an existing volume of paint160. Approximately 10 cc of solvent 162 was added to the reservoir 102,and the recirculating system was operated for approximately 5 minutes toyield a mixed paint 164 as shown in FIG. 7B. The added solvent 162 ofFIG. 7A was mixed with the existing paint substantially completely toyield the mixed paint 164.

The mixed paint 164 was then left without further recirculation forapproximately 5 hours, and the resulting separation of solvent 168 andsettled paint 166 is depicted in FIG. 7C. The separated solvent 168 andthe settled paint 166 were circulated through the recirculating systemagain for approximately 5 minutes; and again, the resulting re-mixing ofthe separated solvent 168 and the settled paint 166 was substantiallycomplete to yield the re-mixed paint 170.

Based on the foregoing example, one can see that achieving a desiredsuspension state of paint can be relatively quick, especially whencompared to some operating durations associated with high-volumeproduction settings. Once such a desirable suspension state is reached,it may be more desirable to be able to maintain such a state for anextended period of operation.

There are a number of operating conditions that can work against such astate over time. For example, there can be leaks in a closed systemwhere loss of materials (e.g., solvent vapor) can occur. In anotherexample, paint particles can build up at various locations in a paintingsystem to cause clogs and other complications.

FIGS. 8A-8C show that one or more features as described in FIGS. 4-7 canallow a recirculating system to operate for an extended period of timewhile maintaining a desired paint suspension level. FIG. 8A shows avolume of paint 132 (approximately ⅛ of pint) loaded in the reservoir102. The initial paint level is indicated by a dotted line 180. Afterapproximately 24 hours of spraying operations and recirculation (e.g.,spraying operation once per hour for the first 9 hours, followed byrecirculation only for the remaining time), the paint volume is shown tohave decreased to a level indicated as 182 in FIG. 8B. FIG. 8C is anenlarged view of the reservoir having the remaining paint 132. Theremaining paint 132 is shown to have a desired level of paintsuspension.

In one test, a 24-hour period of spraying operations and recirculationsimilar to that described in reference to FIGS. 8A-8C resulted inexample spray products listed in Table 1.

TABLE 1 Painted Painted Painted Painted layer layer layer layerthickness thickness thickness thickness Solids Wt. (Sample 1, (Sample 1,(Sample 2, (Sample 2, Time content Avg. frame) flood) frame) flood)(hour) (%) (mg) (μm) (μm) (μm) (μm) 0 65.7 124.43 51.86 44.78 51.6243.45 1 65.7 119.00 60.24 49.84 53.65 51.09 2 66.2 116.10 59.39 50.9261.62 56.48 3 66.1 122.33 45.47 39.74 45.36 36.55 4 66.6 99.10 48.2944.33 52.69 50.34 5 66.4 119.10 39.56 39.36 40.43 35.65 6 66.6 102.9050.91 48.21 57.69 54.70 7 66.7 81.33 48.10 46.05 57.80 56.00 8 67.0111.83 55.64 47.83 58.30 58.87 9 65.6 85.07 35.95 32.30 41.60 34.22 2468.9 94.03 45.41 46.32 47.88 43.82In Table 1, the spraying operations corresponding to the listedmeasurements were performed at approximately the indicated times. For agiven time, the solid content represents the net weight of paint curedin a cup divided by the net weight of paint sprayed into the cup (withthe quotient being multiplied by 100). The weight average (“Wt. Avg.” ofsecond column) represents solids content of the paint after curing. Itis noted that when the paint is not in proper suspension or the closedloop system has a leak that allows the solvent to flash off, there willbe an increase in the solids content since the painting device will notbe spraying as much solvent (e.g., solvent separates to the top of thecartridge and when sprayed from the bottom of the cartridge, more solidswill be sprayed than solvent). Thus, during the curing process, therewill be less solvent to flash off, thereby leaving a higher solidcontent. A similar result can occur if the solvent vapor leaves thepainting system, even if there is proper suspension, since not as muchsolvent is present in the mixture. For each of the two samples in Table1, the frame thickness refers to the cured paint layer thickness at theperimeter of a test panel resulting from two passes; and the floodthickness refers to the cured paint layer thickness at a mid-portion ofthe test panel resulting from two passes. The two sample measurementswere obtained at two locations within the sprayed panel.

FIG. 9A shows a plot of the solid content measurements listed inTable 1. One can see that the solid content values are relative uniform(with a slight overall increasing trend) over the initial 9 hours whenthe hourly spray operations are performed. At the end of the 24-hourperiod, the solid content is shown to increase slightly. However, it isnoted that the overall uniformity is significantly improved overpainting configurations without the peristalsis-based agitation.

FIG. 9B shows plots of the various painted layer thickness measurementslisted in Table 1. One can see that the thicknesses in general show aslight overall decreasing trend; however, it is also noted that theoverall uniformity is significantly improved over paintingconfigurations without the peristalsis-based agitation.

As described herein, a spray apparatus (e.g., 106 in FIGS. 4-6) canreceive metallic paint from a reservoir (102) for spraying, and if notspraying, for recirculation via a recirculator (114). FIGS. 10-17 showvarious examples of how such a spray apparatus can be configured toprovide desired spraying performance and/or to facilitate maintaining ofa desired paint suspension level.

FIG. 10 shows an example configuration of a spray apparatus (106, andalso referred to herein as 200), and FIG. 12 schematically depicts thesame spray apparatus 200. The spray apparatus 200 is shown to include apaint chamber 202 that defines a chamber volume 208. Paint from, forexample, a reservoir (not shown) can enter (arrow 146) the chamber 202through an input tubing 144 and an input fitting 204. Paint can exit(arrow 150) the chamber 202 through a return fitting 206 and a returntubing (e.g., 130 a in FIG. 5) to, for example, a recirculator (notshown).

The spray apparatus 200 is shown to further include a spray nozzleassembly 210 configured to provide a spray output through a nozzle 214.Such a spray output can be atomized by, for example, a pressurized gasentering the nozzle assembly 210 through a tubing 216 and a fitting 212.

The spray apparatus 200 can further include an assembly 230 (shown inFIG. 10, but not in FIG. 12) configured to hold a seal and a returnmechanism for a seat valve pin that allows the paint to be sprayed orrecirculated. Additional details concerning the assembly 230 and relatedfunctionalities are described herein in reference to FIGS. 17A-17E. Theforegoing seal can be configured to prevent leakage of paint out of thetop portion of the chamber 202. In some embodiments, the sealing portionof the assembly 230 can form an upper cap for the chamber 202. Asdescribed herein, actions of the seat valve pin can allow the paint tocome out of the chamber for spraying (through the nozzle assembly 210)or for recirculating (through the fitting 206). Thus, the assembly 230and the seat valve pin can facilitate switching between a recirculationmode to agitate the paint and a spray mode to spray the paint from thechamber 202.

In the example configuration 200 of FIGS. 10 and 12, the volume 208 ofthe chamber 202 can be relatively large, and the return 206 can bespaced vertically from the input 204 by a relatively large distance. Insome situations, one or both of such features can increase thelikelihood of metal flakes settling in the chamber 202. In somesituations, such settling of metal flakes can occur relatively rapidly.

As described herein, when the metal flakes are not in proper suspension,spraying properties can be impacted significantly, and/or the sprayapparatus can become clogged due to build-up of metal flakes. In termsof the resulting painted layers, the foregoing problems can yield unevenpaint thickness and negatively impact the reliability of such layers.Additionally, a relatively large chamber volume can requiresignificantly more paint to purge. In situations where the paint (e.g.,metallic paint) is expensive, such a purging requirement can be verycostly.

FIGS. 11 and 13 show that in some embodiments, a spray apparatus (106,and also referred to herein as 250) can be implemented, and such aconfiguration can address some or all of the foregoing challengesassociated with the example of FIGS. 10 and 12. FIG. 13A schematicallydepicts a side view of the spray apparatus 250 of FIG. 11; and FIG. 13Bschematically depicts a plan view of the same spray apparatus.

The spray apparatus 250 is shown to include a paint chamber 252 thatdefines a chamber volume 258. Paint from, for example, a reservoir (notshown) can enter (arrow 146) the chamber 252 through an input tubing 144and an input fitting 254. Paint can exit (arrow 150) the chamber 252through a return fitting 256 and a return tubing (e.g., 130 a in FIG. 5)to, for example, a recirculator (not shown).

The spray apparatus 250 is shown to further include a spray nozzleassembly 210 configured to provide a spray output through a nozzle(e.g., 214 in FIG. 11). Such a spray output can be facilitated by, forexample, a pressurized gas entering the nozzle assembly 210 through atubing 216 and a fitting 212. In some embodiments, the nozzle assembly210 can be similar to that described in reference to FIGS. 10 and 12.

The spray apparatus 250 can further include an assembly 260 (shown inFIGS. 11 and 13A) configured to hold a seal (331 in FIG. 13A) and areturn mechanism for a seat valve pin (320 in FIG. 13A) that allows thepaint to be sprayed or recirculated. Additional details concerning theassembly 260 and related functionalities are described herein inreference to FIGS. 17A-17E. The foregoing seal 331 can be configured toprevent leakage of paint out of the top portion of the chamber 252. Insome embodiments, the assembly 260 can include a lower portion that isconfigured to form an upper portion of the chamber 252, and to attachthe chamber 252 to a support structure for the peristaltic pump asdescribed herein. As described herein, actions of the seat valve pin 320can allow the paint to come out of the chamber for spraying (through thenozzle assembly 210) or for recirculating (through the fitting 256).Thus, the assembly 260 and the seat valve pin 320 can facilitateswitching between a recirculation mode to agitate the paint and a spraymode to spray the paint from the chamber 252.

In the example configuration 250 of FIGS. 11 and 13, the volume 258 ofthe chamber 252 can be relatively small, and the return 256 can bepositioned at approximately the same height as the input 254 (in theside view of FIG. 13A). In some situations, one or both of such featurescan reduce the likelihood of metal flakes settling in the chamber 252.As described herein, such settling of metal flakes can occur relativelyrapidly.

Accordingly, metal flakes can remain in proper suspension in the chamber252, thereby maintaining desirable spraying properties. In terms of theresulting painted layers, the foregoing features can yield improvementsin uniformity of paint thickness and thereby the reliability of suchlayers. Additionally, such a relatively small chamber volume can requiresignificantly less paint to purge. In situations where the paint (e.g.,metallic paint) is expensive, such a reduced purging volume requirementcan reduce costs associated with spray-painting processes.

The plan view of the configuration in FIG. 13B (where the assembly 260and the seat valve pin 320 are now shown) shows an example configurationwhere input and return fittings 254, 256 are arranged so as to form anangle θ with each other. Such an angle can be adjusted to a value (e.g.,less than 180 degrees, approximately 180 degrees, or greater than 180degrees) to, for example, accommodate tubing connections that are asshort as possible with the paint reservoir and/or the recirculator. Insome embodiments, the angle θ between the input 254 and the return 256can be selected to reduce or minimize turbulence in the volume 258 ofthe chamber 252. For example, the angle θ can be in a range between 30and 150 degrees, 45 and 135 degrees, 60 and 120 degrees, or 80 and 100degrees. In some embodiments, the angle θ can be approximately 90degrees, where it was observed to yield a desirable flow rate throughthe chamber 252 to thereby improve the recirculation rate to keep thepaint properly mixed, and reduce the likelihood of conglomeration of themetal particles (e.g., silver flake) in the chamber 252.

As described in reference to FIGS. 11 and 13, the spray assembly 250 canbe configured to be able to facilitate recirculate and spray modes. FIG.14A schematically depicts a recirculate mode that can be facilitated bythe spray assembly 250. FIG. 14B depicts a spray mode that can befacilitated by the spray assembly 250. Examples of how such recirculateand spray modes can be facilitated by the spray assembly 250 aredescribed herein in reference to FIGS. 17A-17E.

In the recirculate mode, the input paint can enter (arrow 146) thechamber 252 through the input fitting 254, and be directed out (arrow150) of the chamber 252 through the return fitting 256 so as to allowthe paint to be returned to a reservoir. In some embodiments, such areturn of paint can be facilitated by operation of a recirculating pump(e.g., a peristaltic pump) as described herein, and such a returnconfiguration can allow the paint to be agitated in a desirable manner.

In some embodiments, a passageway between the chamber 252 and the nozzleassembly 210 can be blocked substantially completely when the sprayassembly 250 is in the recirculate mode. An example of such blocking isdescribed herein in reference to FIGS. 17A-17E.

In the spray mode, the input paint can enter (arrow 146) the chamber 252through the input fitting 254, and be directed out (arrow 262) of thechamber 252 to the nozzle assembly 210 so as to facilitate the spraymode. In some embodiments, passage of paint out of the chamber 252through the return 256 can be inhibited by shutting off therecirculating pump (e.g., the peristaltic pump) when in the spray mode.The recirculating pump being off while in the spray mode can also avoidpulsing effects of the pump (e.g., resulting from peristalsis action)impacting the spray output. The passageway between the chamber 252 andthe nozzle assembly 210 can be opened when the spray assembly 250 is inthe spray mode. An example of such opening of the passageway isdescribed herein in reference to FIGS. 17A-17E. The paint provided tothe nozzle assembly 210 can be forced out from the chamber 252 by thepressure of the input paint (146). In some embodiments, a spray pattern270 can be obtained by an atomizer supplied with a pressurized gas 218provided through the fitting 212. An example of such an atomizer isdescribed herein in reference to FIG. 17A.

In some embodiments, switching between spray and recirculate modes canbe implemented so that a number of components in the painting system(e.g., 100 in FIG. 4) are controlled in a coordinated manner. Forexample, a spray mode can include the recirculation pump being shut offto prevent recirculation and to avoid pulsing effects during spraying.Also, the foregoing opening of the passageway between the chamber 252and the nozzle assembly 210 (in FIG. 14B) can be effectuated (asdescribed by example in FIGS. 17A-17E) by providing compressed air to anactuation mechanism (e.g., 338 in FIG. 17A).

In an example of a recirculate mode, the foregoing passageway betweenthe chamber 252 and the nozzle assembly 210 (in FIG. 14B) can be closed(as described by example in FIGS. 17A-17E) by shutting off thecompressed air to the actuation mechanism (338 in FIG. 17A). Also, thecirculation pump can be turned on to allow recirculation of the paint asdescribed herein.

In some embodiments, and as depicted in FIG. 4, some or all of theswitching functionalities and/or other functionalities associated withthe painting system can be coordinated by a controller 400. In someembodiments, such a controller can cooperate with one or more othercontrollers associated with production components upstream and/ordownstream of the painting system.

FIG. 15 shows that in some embodiments, the spray assembly 250 asdescribed herein can be implemented so that its chamber volume 258 isdimensioned to facilitate maintaining of proper paint suspension. In thecontext of an example cylindrical shape, suppose that the volume 258 hasa diameter D and a height H. A passageway into the volume 258 is shownto be positioned at a height h_(in) and have a diameter d_(in). Apassageway out of the volume 258 to a recirculator is shown to bepositioned at a height h_(recirc) and have a diameter d_(recirc). Apassageway out of the volume 258 to a nozzle assembly (210) is shown tobe positioned at a bottom surface of the volume 258 and have a diameterd_(nozzle). In some implementations, some or all of the foregoing designparameters can be selected to achieve one or more desired paintsuspension properties and/or spraying performance.

In the example shown, the heights (depicted by lines 280 and 282) of theinput and return passageways can be generally the same. Because of theapproximately same height of the input and return passageways, thevertical dimension H of the volume 258 can be reduced or minimized. Sucha reduced dimension can provide a number of advantages, including butnot limited to, reduced purge volume, a flow of paint that is morelaminar between the input and return passageways, and simpler selectordesigns that have less or no sharp features (such as screw threads)where paint particles tend to accumulate.

In some implementations, the foregoing same-height (of input and returnpassageways) feature can be modified to accommodate some other designconsiderations. As shown in FIGS. 16A and 16B, such heights can bedifferent, and the spray assembly 250 can retain some or all of thedesirable features described herein. For example, FIG. 16A shows thatthe recirculating output's height 282 can be higher than the input'sheight 280 by an amount Δh. In another example, FIG. 16A shows that therecirculating output's height 282 can be lower than the input's height280 by an amount Δh.

As described herein in reference to FIGS. 10-14, a spray assembly (e.g.,200 in FIGS. 10 and 12, or 250 in FIGS. 11 and 13) can be configured tobe in a spray mode or a recirculate mode. FIGS. 17A-17E show variousviews of an example mechanism that can be implemented to facilitate suchmodes and to allow switching between such modes. FIG. 17A schematicallydepicts a cutaway view of a spray assembly 300 having a mechanism forachieving the foregoing functionalities. FIG. 17B shows a sectional viewof a portion 322 of a paint chamber 302 of the spray assembly 300. FIG.17C shows a side sectional view of the same portion 322. FIG. 17D showsa more detailed view of a portion 324 when the spray assembly 300 is inthe recirculate mode. FIG. 17E shows a more detailed view of the sameportion 324 when the spray assembly 300 is in the spray mode.

The example configuration shown in FIG. 17A is depicted in the contextof the examples described herein in reference to FIGS. 11, 13 and 14. Itwill be understood, however, that one or more features associated withthe spray assembly 300 can also be implemented in other configurations(e.g., examples of FIGS. 10 and 12).

The example configuration of FIG. 17A does not include a heating portionbetween a paint input and the portion 324. In some embodiments, such aheating portion can be included in situations where heating of thematerial being sprayed improves the spraying characteristics. Thus, itwill be understood that such a heating portion may or may not beincluded in various embodiments of the spray assembly as describedherein. The example configurations described in reference to FIGS. 10-13do not have such a heating portion.

In the example configuration 300, the chamber 302 is shown to define avolume 304 dimensioned to allow a valve pin 320 (also referred to hereinas a needle) to move up (e.g., in the spray mode) and down (e.g., in therecirculate mode). Such a switching action can allow paint (depicted asan arrow 310) to flow from an input 312 to a paint output (in theportion 324) in the spray mode, or to a recirculation output 313 in therecirculate mode. In some embodiments (e.g., the examples of FIGS.10-13), the input fitting 312 can be coupled directly with the interiorof the chamber 302 without an intervening input manifold. Similarly, therecirculation output fitting 313 can be coupled directly with theinterior of the chamber 302 without an intervening output manifold.

Within the chamber 302, the paint can move from the input fitting 312 tothe paint output area through a conduit 306 (see FIGS. 17B and 17C)defined in the volume 304 between the wall of the chamber 302 and thevalve pin 320. The sectional area of the conduit defined by the wall ofthe chamber 302 and the valve pin 320 (depicted as 306 in FIGS. 17B and17C) can be selected to achieve desired functionalities such as paintflow and/or purge volume. Such a selection of the sectional area can befacilitated by, for example, providing different diameters of the valvepin 320 and/or the volume 304 of the chamber 302.

FIGS. 17D and 17E schematically depict the paint output of the portion324. The chamber 302 is shown to include an end cap 350 so as to definean end space 352. The end cap 350 can define or include a spray aperture354 dimensioned to allow passage of the paint from the end space 352 toa nozzle 317 and an atomizer 314 (shown in FIG. 17A) when opened (FIG.17E). When the spray aperture 354 is closed (FIG. 17D), the paint can beretained in the end space 352 before being pumped out for recirculation.

In some embodiment, the foregoing movement of paint through the sprayaperture 354 (e.g., when in the spray mode) can be facilitated by thepaint pressure provided from the reservoir (e.g., 102 in FIG. 6) whichis in turn provided by compressed air through the tube 142 (FIG. 6).During such a spray mode, the recirculation pump 120 (e.g., in FIG. 6)is preferably turned off to avoid pulsating spray output through theaperture 354. In some embodiments, the atomizer 314 can be a coaxial airbased atomizer operated by pressurized air through an input 315.

The spray aperture 354 is shown to include a valve seat 364 dimensionedto mate with a tip 360 of the valve pin 320. In the closed configuration(recirculate mode) of FIG. 17D, the surface of the valve tip 360 canmate with the corresponding surface of the valve seat 364 tosubstantially seal the spray aperture 354. In the open configuration(spray mode) of FIG. 17E, the valve tip 360 can be retracted away fromthe valve seat 364 so as to allow flow of paint (arrow 370) from the endspace 352 through the spray aperture 354. Although described in thecontext of a pointed tip shape of the valve pin 320 and thecorresponding valve seat shape, it will be understood that other valveand seat shapes can also be utilized.

As shown in FIG. 17A, the foregoing seating and retraction of the valvepin 320 can be actuated by an air piston 330 that is coupled to thevalve pin 320. In the example shown, a return spring assembly 338 can beconfigured to push the valve pin 320 into its seated position to yieldthe recirculate mode. To retract the valve pin 320 to thereby actuatethe spray mode, pressurized air (arrow 334) can be provided to the airpiston 330 through an air inlet 332. The pressurized air can then pushup on the air piston 330 to retract the valve pin 320 to allow the paintto pass through the spray aperture 354. To seat the valve pin 320 tothereby stop the spraying, the pressurized air (334) can be turned off,and a spring 339 can push down on the piston 330, and thus the valve pin320.

The foregoing up and down movements of the valve pin 320 are indicatedby an arrow 336. Such movements of the valve pin 320 are preferablyachieved while keeping the paint within the chamber 302 and away fromthe spring assembly 338 and the related actuation mechanisms. In someembodiments, a seal 331 can be provided and configured to inhibit suchleakage of paint upward from the chamber 302. In some embodiments, theseal 331 can be, for example, a U-cup seal mounted in an inverted manneras shown, with the valve pin extending through its center portion. Sucha seal can be configured to maintain or increase its sealing propertywhen pressure (e.g., paint pressure from the chamber 302) is provided.

In the example shown in FIG. 17A, an adjustment device 340 can beprovided and configured to, for example, allow adjustment of retractiontravel of the valve pin 320 when actuated by the air piston. In someembodiments, such an adjustment device can be configured to provide finemicro-adjustment capability.

In some embodiments, various features associated with the foregoingswitching functionality between recirculate and spray modes as describedin reference to FIGS. 17A-17E can be implemented in any of the examplespray apparatus described herein in reference to FIGS. 4-16 or anycombination thereof. In some embodiments, the coaxial air based atomizercan also be utilized in the same spray apparatus.

As described herein, one or more features of the present disclosure canprovide a number of advantageous features for spraying and/orrecirculation of metallic paint in applications such as formation ofmetallic paint layers on panels having radio-frequency modules. Forexample, a desired suspension of metallic particles in solution can beachieved quickly and maintained for an extended period of time. Inanother example, a spray apparatus and its coupling with a recirculatorand a paint reservoir can be configured to reduce the purge volume by,for example, a reduced paint chamber volume and reduced pathlengthsbetween the coupled components. In yet another example, the sprayapparatus can be configured to reduce the likelihood of paint particlesaccumulating within the paint chamber volume, as well as its input andoutput(s).

The foregoing examples of issues associated with painting applicationsand the various features that can address such issues can become muchmore pronounced in high-throughput mass production settings. Forexample, negative effects in production volume, yield and qualityresulting from disruptions and stoppages associated with conventionalpainting systems not having the advantageous features as describedherein can be substantial. Further, inefficient use of expensivematerials such as metallic paint can result from such conventionalpainting systems not having the advantageous features as describedherein can also be substantial.

In the context of high-throughput mass production settings, if aconventional painting system is in series with other processing systems(upstream and/or downstream), such processing systems will likely needto be suspended during cleaning and/or maintenance of the paintingsystem (e.g., to clean out accumulated paint resulting in clogged pathsand parts), thereby significantly interrupting the production volume.Even if a number of such painting systems are provided in parallel, theoverall maintenance/cleaning frequency simply increases, typicallyrequiring increased time and resource of operators.

As described herein, need for and frequency of such cleaning and/ormaintenance can be reduced significantly, and in some situations, may beeliminated. For example, a painting system can be configured to provideand maintain a desired paint particle suspension level over a 12-hourperiod. It is also possible that such a period between maintenance canbe extended beyond 12 hours.

Aside from the advantages associated with reduced frequency of cleaningand/or cleaning, improved consistency in the quality of painted layerscan be realized. Such consistency, resulting from one or more featuresas described herein, translates into significantly improved yield andquality of the modules manufactured in mass quantities.

In some embodiments, one or more features as described herein can beimplemented during manufacture of packaged electronic modules, includingradio-frequency (RF) modules such as a power amplifier (PA) module, alow noise amplifier (LNA) module, a switching module, a front-endmodule, a global positioning system (GPS) module, a controller module,an application processor module, an audio module, a display interfacemodule, a memory module, a digital baseband processor module, anaccelerometer module, a power management module, a transceiver module,or a module configured to provide one or more functionalities associatedwith such modules.

The present disclosure describes various features, no single one ofwhich is solely responsible for the benefits described herein. It willbe understood that various features described herein may be combined,modified, or omitted, as would be apparent to one of ordinary skill.Other combinations and sub-combinations than those specificallydescribed herein will be apparent to one of ordinary skill, and areintended to form a part of this disclosure. Various methods aredescribed herein in connection with various flowchart steps and/orphases. It will be understood that in many cases, certain steps and/orphases may be combined together such that multiple steps and/or phasesshown in the flowcharts can be performed as a single step and/or phase.Also, certain steps and/or phases can be broken into additionalsub-components to be performed separately. In some instances, the orderof the steps and/or phases can be rearranged and certain steps and/orphases may be omitted entirely. Also, the methods described herein areto be understood to be open-ended, such that additional steps and/orphases to those shown and described herein can also be performed.

Some aspects of the systems and methods described herein canadvantageously be implemented using, for example, computer software,hardware, firmware, or any combination of computer software, hardware,and firmware. Computer software can comprise computer executable codestored in a computer readable medium (e.g., non-transitory computerreadable medium) that, when executed, performs the functions describedherein. In some embodiments, computer-executable code is executed by oneor more general purpose computer processors. A skilled artisan willappreciate, in light of this disclosure, that any feature or functionthat can be implemented using software to be executed on a generalpurpose computer can also be implemented using a different combinationof hardware, software, or firmware. For example, such a module can beimplemented completely in hardware using a combination of integratedcircuits. Alternatively or additionally, such a feature or function canbe implemented completely or partially using specialized computersdesigned to perform the particular functions described herein ratherthan by general purpose computers.

Multiple distributed computing devices can be substituted for any onecomputing device described herein. In such distributed embodiments, thefunctions of the one computing device are distributed (e.g., over anetwork) such that some functions are performed on each of thedistributed computing devices.

Some embodiments may be described with reference to equations,algorithms, and/or flowchart illustrations. These methods may beimplemented using computer program instructions executable on one ormore computers. These methods may also be implemented as computerprogram products either separately, or as a component of an apparatus orsystem. In this regard, each equation, algorithm, block, or step of aflowchart, and combinations thereof, may be implemented by hardware,firmware, and/or software including one or more computer programinstructions embodied in computer-readable program code logic. As willbe appreciated, any such computer program instructions may be loadedonto one or more computers, including without limitation a generalpurpose computer or special purpose computer, or other programmableprocessing apparatus to produce a machine, such that the computerprogram instructions which execute on the computer(s) or otherprogrammable processing device(s) implement the functions specified inthe equations, algorithms, and/or flowcharts. It will also be understoodthat each equation, algorithm, and/or block in flowchart illustrations,and combinations thereof, may be implemented by special purposehardware-based computer systems which perform the specified functions orsteps, or combinations of special purpose hardware and computer-readableprogram code logic means.

Furthermore, computer program instructions, such as embodied incomputer-readable program code logic, may also be stored in a computerreadable memory (e.g., a non-transitory computer readable medium) thatcan direct one or more computers or other programmable processingdevices to function in a particular manner, such that the instructionsstored in the computer-readable memory implement the function(s)specified in the block(s) of the flowchart(s). The computer programinstructions may also be loaded onto one or more computers or otherprogrammable computing devices to cause a series of operational steps tobe performed on the one or more computers or other programmablecomputing devices to produce a computer-implemented process such thatthe instructions which execute on the computer or other programmableprocessing apparatus provide steps for implementing the functionsspecified in the equation (s), algorithm(s), and/or block(s) of theflowchart(s).

Some or all of the methods and tasks described herein may be performedand fully automated by a computer system. The computer system may, insome cases, include multiple distinct computers or computing devices(e.g., physical servers, workstations, storage arrays, etc.) thatcommunicate and interoperate over a network to perform the describedfunctions. Each such computing device typically includes a processor (ormultiple processors) that executes program instructions or modulesstored in a memory or other non-transitory computer-readable storagemedium or device. The various functions disclosed herein may be embodiedin such program instructions, although some or all of the disclosedfunctions may alternatively be implemented in application-specificcircuitry (e.g., ASICs or FPGAs) of the computer system. Where thecomputer system includes multiple computing devices, these devices may,but need not, be co-located. The results of the disclosed methods andtasks may be persistently stored by transforming physical storagedevices, such as solid state memory chips and/or magnetic disks, into adifferent state.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” The word “coupled”, as generally usedherein, refers to two or more elements that may be either directlyconnected, or connected by way of one or more intermediate elements.Additionally, the words “herein,” “above,” “below,” and words of similarimport, when used in this application, shall refer to this applicationas a whole and not to any particular portions of this application. Wherethe context permits, words in the above Detailed Description using thesingular or plural number may also include the plural or singular numberrespectively. The word “or” in reference to a list of two or more items,that word covers all of the following interpretations of the word: anyof the items in the list, all of the items in the list, and anycombination of the items in the list. The word “exemplary” is usedexclusively herein to mean “serving as an example, instance, orillustration.” Any implementation described herein as “exemplary” is notnecessarily to be construed as preferred or advantageous over otherimplementations.

The disclosure is not intended to be limited to the implementationsshown herein. Various modifications to the implementations described inthis disclosure may be readily apparent to those skilled in the art, andthe generic principles defined herein may be applied to otherimplementations without departing from the spirit or scope of thisdisclosure. The teachings of the invention provided herein can beapplied to other methods and systems, and are not limited to the methodsand systems described above, and elements and acts of the variousembodiments described above can be combined to provide furtherembodiments. Accordingly, the novel methods and systems described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the methods andsystems described herein may be made without departing from the spiritof the disclosure. The accompanying claims and their equivalents areintended to cover such forms or modifications as would fall within thescope and spirit of the disclosure.

What is claimed is:
 1. A painting system for fabricating electronicmodules, the system comprising: a reservoir having an input and anoutput, the reservoir implemented to hold a volume of metallic paint;and a recirculator coupled to the reservoir and implemented to receivemetallic paint that has left the output of the reservoir and pump themetallic paint back to the input of the reservoir by peristalsis actionto agitate the volume of metallic paint in the reservoir.
 2. Thepainting system of claim 1 further comprising a spray apparatusimplemented between the output of the reservoir and the recirculator,the spray apparatus including a nozzle assembly configured to be capableof spraying the metallic paint.
 3. The painting system of claim 2wherein the spray apparatus includes a selector configured to route themetallic paint to either the nozzle assembly for spraying of themetallic paint or the recirculator for pumping the metallic paint backto the reservoir.
 4. The painting system of claim 3 wherein the selectorincludes a seal mechanism.
 5. The painting system of claim 2 wherein therecirculator includes a peristaltic pump.
 6. The painting system ofclaim 5 wherein the peristaltic pump is a rotary-type peristaltic pump.7. The painting system of claim 6 wherein the peristaltic pump isconfigured to operate at different speeds to yield different flow rates.8. The painting system of claim 5 wherein a recirculating path definedby a path from the reservoir to the spray apparatus, a path from thespray apparatus to the peristaltic pump, and a path from the peristalticpump to the reservoir, is substantially closed to inhibit vaporizationloss.
 9. The painting system of claim 8 wherein the recirculating pathhas a length that is less than approximately 30 inches to reduce apurging volume.
 10. The painting system of claim 9 wherein the length isless than approximately 15 inches.
 11. The painting system of claim 7wherein a relatively compact size of the peristaltic pump allows thespray apparatus and the reservoir to be positioned relatively close tothe peristaltic pump, thereby allowing a relatively short length for therecirculating path.
 12. The painting system of claim 7 wherein each ofthe path from the spray apparatus to the peristaltic pump and the pathfrom the peristaltic pump to the reservoir includes a tubing having abore diameter selected to yield a desired flow rate of the recirculatingpath.
 13. The painting system of claim 12 wherein an increase in thebore diameter results in an increase in the flow rate.
 14. The paintingsystem of claim 7 wherein the reservoir further includes a gas inputconfigured to receive a pressurized gas to push the metallic paint fromthe reservoir to the spray apparatus.
 15. The painting system of claim 1wherein the system is capable of establishing a desired level ofsuspension for the metallic paint from a separated state withinapproximately 5 minutes.
 16. The painting system of claim 15 wherein thesystem is capable of substantially maintaining the desired level ofsuspension for at least 9 hours.
 17. The painting system of claim 16wherein the system is capable of substantially maintaining the desiredlevel of suspension for at least 12 hours.
 18. A recirculating systemfor agitating metallic paint awaiting spray-application to form aconductive layer for one or more electronic modules, the systemcomprising a peristaltic pump configured to pump the metallic paint froma reservoir and return unsprayed metallic paint to the reservoir.
 19. Amethod for applying metallic paint during fabrication of electronicmodules, the method comprising: providing a reservoir to hold a volumeof metallic paint awaiting spray-application, the reservoir including aninput and an output; providing a spray apparatus capable of being in aspray mode and a recirculate mode; providing the metallic paint from thereservoir to the spray apparatus through a first path to allowspray-application of the metallic paint when the spray apparatus is inthe spray mode; and returning the metallic paint from the sprayapparatus to the reservoir through a second path by peristalsis when thespray apparatus is in the recirculate mode.